To a solution of 15.023 g (70.438 mmol) of 5-benzyl-4,5,6,7-tetrahydrofuro[3,2-c]pyridine in 100 ml of methanol, 2 ml of acetic acid was added, followed by hydrogenation over 5 g of 10% palladium-carbon (50% hydrated) at room temperature at atmospheric pressure for 8 hours. The mixture was filtered using Celite to remove the catalyst; the Celite was washed with methanol 3 times. The combined methanol solution was evaporated under reduced pressure. The resulting residue (crude 4,5,6,7-tetrahydrofuro[3,2-c]pyridine) was dissolved in 100 ml of dichloromethane. To this solution, a solution of 15.4 g (70.4 mmol) of di-tert-butyl dicarbonate in 50 ml of dichloromethane was added dropwise at room temperature, followed by stirring for 0.5 hours. The solvent was distilled off under reduced pressure; the resulting crude product was purified by silica gel column chromatography (hexane/ethyl acetate=15/1) to yield 5-tert-butoxycarbonyl-4,5,6,7-tetrahydrofuro[3,2-c]pyridine as a mixture with di-tert-butyl dicarbonate.
